Surah 4:127 different rulings for the prophet

[miracle114]

Salaam all,

In 4:127 Allah says he has given a ruling to the prophet and in the Book as well.
What is the wisdom behind this? Why has Allah mentioned this?
One could assume that the prophet had a separate ruling because he had direct revelation from God but the revelation for al mankind is the book so we are to adhere to the book.
OR traditionalists might argue now that the prophet had rulings/laws revealed to him that were recorded separately and need to be followed.

Peace brothers and sisters